github.com/cenkalti/backoff/v5 v5.0.3: NewTicker

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify github.com/cenkalti/backoff/v5.NewTicker in pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3
Demonstrate these symbols/APIs:
  - github.com/cenkalti/backoff/v5.NewTicker

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:3c890410d88e92f2c3003a7eb50d5c952ace4865d14f09b77e3ab841669d1c67","contract":["NewTicker returns a Ticker with a non-nil C channel","NewTicker calls Reset on the provided BackOff upon creation","NewTicker delivers at least one initial tick even when BackOff stops immediately","Ticker.Stop stops tick delivery and closes the C channel","Ticker.Stop is safe to call multiple times without panicking","NewTicker delivers periodic ticks according to the BackOff interval"],"goal":"verify github.com/cenkalti/backoff/v5.NewTicker in pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3","kind":"HOW","packages":["pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3"],"schemaVersion":1,"symbols":["github.com/cenkalti/backoff/v5.NewTicker"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3"],"schemaVersion":1,"subject":"pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3","symbols":["github.com/cenkalti/backoff/v5.NewTicker"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/cenkalti/backoff/v5 v5.0.3

github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=

package main

import (
	"fmt"
	"time"

	"github.com/cenkalti/backoff/v5"
)

func main() {
	b := backoff.NewConstantBackOff(10 * time.Millisecond)
	ticker := backoff.NewTicker(b)
	defer ticker.Stop()

	count := 0
	for tick := range ticker.C {
		count++
		fmt.Printf("Tick %d received at %v\n", count, tick)
		if count >= 3 {
			break
		}
	}
	fmt.Println("Ticker demonstration finished successfully.")
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/cenkalti/backoff/v5.NewTicker in pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3"
  ],
  "symbols": [
    "github.com/cenkalti/backoff/v5.NewTicker"
  ]
}

package main

import (
	"fmt"
	"os"
	"time"

	"github.com/cenkalti/backoff/v5"
)

type resetTrackerBackOff struct {
	resetCalled bool
}

func (r *resetTrackerBackOff) Reset() {
	r.resetCalled = true
}

func (r *resetTrackerBackOff) NextBackOff() time.Duration {
	return backoff.Stop
}

func main() {
	// Assertion 1: NewTicker returns a Ticker with a non-nil C channel
	{
		b := &backoff.StopBackOff{}
		ticker := backoff.NewTicker(b)
		if ticker == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: ticker is nil\n")
			os.Exit(1)
		}
		if ticker.C == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: ticker.C is nil\n")
			os.Exit(1)
		}
		ticker.Stop()
	}

	// Assertion 2: NewTicker calls Reset on the provided BackOff upon creation
	{
		tracker := &resetTrackerBackOff{}
		ticker := backoff.NewTicker(tracker)
		if !tracker.resetCalled {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: Reset was not called on BackOff\n")
			os.Exit(1)
		}
		ticker.Stop()
	}

	// Assertion 3: NewTicker delivers at least one initial tick even when BackOff stops immediately
	{
		ticker := backoff.NewTicker(&backoff.StopBackOff{})
		ticks := 0
		for range ticker.C {
			ticks++
		}
		if ticks != 1 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected exactly 1 tick, got %d\n", ticks)
			os.Exit(1)
		}
	}

	// Assertion 4: Ticker.Stop stops tick delivery and closes the C channel
	{
		ticker := backoff.NewTicker(backoff.NewConstantBackOff(5 * time.Millisecond))
		select {
		case _, ok := <-ticker.C:
			if !ok {
				fmt.Fprintf(os.Stderr, "assertion 4 failed: channel closed prematurely\n")
				os.Exit(1)
			}
		case <-time.After(1 * time.Second):
			fmt.Fprintf(os.Stderr, "assertion 4 failed: timeout waiting for initial tick\n")
			os.Exit(1)
		}
		ticker.Stop()

		closed := false
		timer := time.NewTimer(1 * time.Second)
		defer timer.Stop()
		for !closed {
			select {
			case _, ok := <-ticker.C:
				if !ok {
					closed = true
				}
			case <-timer.C:
				fmt.Fprintf(os.Stderr, "assertion 4 failed: ticker.C not closed after Stop\n")
				os.Exit(1)
			}
		}
	}

	// Assertion 5: Ticker.Stop is safe to call multiple times without panicking
	{
		ticker := backoff.NewTicker(&backoff.StopBackOff{})
		ticker.Stop()
		ticker.Stop()
		ticker.Stop()
	}

	// Assertion 6: NewTicker delivers periodic ticks according to the BackOff interval
	{
		interval := 5 * time.Millisecond
		ticker := backoff.NewTicker(backoff.NewConstantBackOff(interval))
		defer ticker.Stop()

		ticks := 0
		timeout := time.After(500 * time.Millisecond)
		for ticks < 3 {
			select {
			case _, ok := <-ticker.C:
				if !ok {
					fmt.Fprintf(os.Stderr, "assertion 6 failed: ticker closed unexpectedly\n")
					os.Exit(1)
				}
				ticks++
			case <-timeout:
				fmt.Fprintf(os.Stderr, "assertion 6 failed: timeout waiting for ticks\n")
				os.Exit(1)
			}
		}
		if ticks != 3 {
			fmt.Fprintf(os.Stderr, "assertion 6 failed: expected 3 ticks, got %d\n", ticks)
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed successfully.")
}